Why does this galaxy have such a long curvy tail coming off it? That river of sunlike stars, going into deep space, was pulled away from NGC 7714 due to the gravitational pull of a galaxy passing by. »1/29/15 3:23pm 1/29/15 3:23pm

This is SNR E0519-69.0, an expanding shell of debris around a star that exploded in the Large Magellanic Cloud, a satellite galaxy to the Milky Way. The red lines are the outer edges of the explosion (visible light) and the blue glow is the superhot gas (millions of degrees hot, in X-Ray). »1/27/15 3:27pm 1/27/15 3:27pm

European astronomers using using the XMM-Newton X-ray space telescope have captured a glimpse of an unprecedented rogue galaxy that's smashing through other galaxies at a rate of 814 miles (1,310 km) per second. »1/15/15 4:40pm 1/15/15 4:40pm

You're looking at the biggest and sharpest image ever taken of the Andromeda Galaxy. Though it only includes one third of the massive celestial object, the image contains a jaw-dropping 1.5 billion pixels.»1/06/15 3:30pm 1/06/15 3:30pm

Blaze of glory. NGC 2207 and IC 2163, two spiral galaxies in the process of merging, turn out to have an unusual number of "ultraluminous X-ray sources" according to the Chandra X-Ray Observatory. What's more, astronomers have found three supernova explosions in the pair in the past 15 years. »12/19/14 4:00pm 12/19/14 4:00pm

Bursting with stars: Markarian 209, a blue compact dwarf galaxy, is captured in the middle of an intense burst of star formation, as seen in the light blue cloudy region in the top right corner. The dominant population of stars is under 3 million years old, compared with our 4.6 billion year-old sun. [Hubble/ESA] »12/15/14 7:00pm 12/15/14 7:00pm

You probably already knew today is Black Hole Friday. To celebrate, NASA and other agencies have been posting black hole stuff. Like the above, an artist's conception of a black hole five times the mass of the one at our galaxy's center, in a superdense galaxy 1/500th the diameter of our own, the M60-UCD1 dwarf galaxy. »11/28/14 5:00pm 11/28/14 5:00pm

How does a galaxy evolve — and how do we know what we know about that process? James Geach is here to take all of our questions about the process and the observation of galaxy formation. »11/12/14 10:42am 11/12/14 10:42am

For the first time ever, astronomers have observed a galaxy in its initial phase of development. The discovery of a massive galaxy, dubbed "Sparky," reveals a dense galactic core that's producing new stars at a ferocious rate. »8/28/14 11:40am 8/28/14 11:40am

In a galaxy more than 12 billion light years from Earth, stars are being created at a rate 500 times faster than in our Milky Way. That cosmic fertility comes at a price: the galaxy is quickly running out of fuel. But it's also teaching us more about galaxy formation in the early universe. »7/09/14 12:06pm 7/09/14 12:06pm

The Chandra X-Ray Observatory recently released four of the most stunning images of galaxies we've ever seen — but these mind-blowing pictures couldn't have come into existence without the help of amateur astronomers and photographers. »4/30/14 6:00pm 4/30/14 6:00pm

Monday is the cosmic wonder-killer. It's really hard to remember that we live in a beautiful, insane universe, crammed with astonishing miracles of creation. So as a public service, we're sharing some absolutely stunning images of galaxies in deep space. Look at these, and remember to reach for greatness! »4/28/14 4:20pm 4/28/14 4:20pm

This cross-section of the universe, snapped by the Hubble, takes us about halfway to the universe's observable end — showing us things that you could only see with your eyes if your eyesight's power was magnified by a billion. »4/17/14 2:12pm 4/17/14 2:12pm

We already knew that this ancient galaxy cluster (nicknamed "El Gordo") was the largest of the distant galaxies that we had spotted, but it turns out we've been massively underestimating its size. How did astronomers figure it out? Simple. They weighed it. »4/03/14 6:00pm 4/03/14 6:00pm